The youths, together with union activists, have vowed to push ahead with what has been billed as the "April 12 Uprising" to force Mswati to concede to demands for democratic reforms.

Political parties were banned in Swaziland in 1973.

The expected uprising in Swaziland coincides with the culmination of political turmoil in another African state with the arrest of former Ivory Coast president Laurent Gbagbo.

Mswati's police yesterday arrested the president of the Swaziland National Union of Students, Maxwell Dlamini, the national organising secretary of the Swaziland United Democratic Front, Themba Mabuza, the front's deputy secretary, Simanga Ginindza, and the deputy president of the Swaziland Youth Congress, Sifiso Mabuza.

The arrests were made at one of the many roadblocks that have been set up across the country.

According to the Swaziland Solidarity Network, the four were travelling from Emalahleni, where they had attended a meeting in preparations for the protests.

"At the time of the release of this statement [yesterday afternoon], no one knew of their whereabouts," the network said. "They have not been charged with anything and their arrest is a well known tactic by the regime to try to sabotage the mass protests."

The protesters are expected to be confronted by the police and the military today.

Political analyst Adam Habib, of the University of Johannesburg, warned protesters to expect a protracted showdown with the 25-year-old Mswati regime.

"It will take more than one march to influence a transitional democratic change in Swaziland. It is clear that there is widespread unhappiness in Swaziland. I don't think it can happen with just one march. It will require sustained protests that will have the ability to withstand repression," he said.

Protesters, said Habib, should be prepared to die for change. He made reference to recent protests in Egypt, Tunisia and Libya.

He said South Africa could use its economic influence to effect regime change but that was not desirable.

Thousands of supporters of SA trade unions federation Cosatu are expected to assist the protesters by mounting a blockade and shutting down the Oshoek border post in Mpumalanga.

Cosatu, the SA Communist Party and the Swaziland Solidarity Network called on international and South African civil organisations to join a demonstration at the kingdom's embassy in Pretoria today in solidarity with the Swaziland protests. Network spokesman Lucky Lukhele said: "The demonstration is in support of popular mobilisation by the people of Swaziland for the regime of King Mswati to relinquish its authoritarian position of power and give way to the legitimate aspirations of the people for a democratic Swaziland."

Mswati, whose opulent lifestyle has triggered domestic protests and international ridicule, has over the years been criticised for demanding a private jet and private palaces for each of his 13 wives. Swaziland - Africa's last absolute monarchy - has a population estimated at 1.1million, most of whom are unemployed. The country has been ravaged by HIV.

Cosatu's second deputy president, Zingiswa Losi, said the days of Mswati were "surely numbered".

"We want to make a call to King Mswati that your time is over.

"King Mswati, you have a choice to allow for a negotiated exit or be forced out of power.

"The people of Swaziland want democracy now and they want democracy on their own terms and not your terms.

"The people of Swaziland are not prepared to compromise their freedom, by their action and resilience we can see that they are not prepared to waste another day without winning back their freedom."